In the old days, I know that when they built a concrete block basement,
the wooden floor joists were just set on top of the block walls, and
they would make the top row of block with a solid topped block (no
exposed core). Then after the wooden joists were set in place, they
would put a thick bead of mortar on the inside, on top of the block
I've lived in several homes built in this manner. I guess they figured
the weight of the house would hold it in place, and that mortar bead
added to this, as well as keeping air from leaking and insects and
rodents from entering.
The problem with that concept is that if a tornado or hurricane hits the
area, it dont take much to knock the house off the foundation.
I'm planning to build a small summer cabin. It will be set on a
concrete block foundation, either as a crawl space, or possibly a usable
basement depending on cost. Since the cabin will be small, that would
mean is weighs less, and thus would probably make it blow off the
foundation easier. This is not an area that gets hurricanes, but
tornados are always a possibility.
My question is what's a better method to attach the house floor to the
They suggest putting an anchor bolt every 3' to 4' in the last (top) run
of the blocks. I guess that would mean having an open cored block every
3rd or 4th block, and filling the block core with concrete to hold that
anchor. But that brings up two questions.
1. Filling a block's core generally means all the cores below it would
need to get filled, and thaT would take a lot of concrete. Unless a wad
of newspaper or some insulation is crammed in the blocks in the row
below the top one first.
2. Using floor joists laid on their narrow edge (such as 2x8's), this
anchor would end up with no wood to attach to, unless a 2x8 was laid
flat first, and then the floor joists laid on top of that, which is not
something I've seen. (Or is there some sort of bracket made for this
Then too, making sure these anchors dont und up directly under a joist
might be tricky too, because the location of each joist would have to be
measured and marked on the blocks first.
Anyone have any tips?
Please, if you want to tell me to contact a building inspector, or hire
a professional, dont even reply. This is a DIY project in a rural area.
There wont be any professionals involved, nor any inspections, other
than getting a building permit (to keep the local officials happy and
wealthy). I already inquired, they said that as long as it's not a full
time home, I just need a permit to build, and they need to know the size
and type of construction. (so they can raise my property taxes to suit